Double magneto generator unit



Dec. 15, 1942. w. E. scHwARzMANN ETAL 2,305,448

DOUBLE MAGNET@ GENERATOR UNIT Filed May 2, 1942 3 Sheens-Sheet 1 INVENToRs Wal/ww scam/17mm ,P c/A RL fs SMN/NE Dec. 15, 1942.

w. E. scHwARzMANN Erm. 2,305,448

DOUBLE MAGNETO GENERATOR UNIT Filed May 2. 1942 5 Shees-Sheet 2 Dec- 15, 1942 w. E. scHwARzMANN ETAL DOUBLE MAGNET() GENERATOR UNIT Filed May 2, 1942 3 Sheets-Sheet 5 A TTORNE Y Patented Dec. 15, 1942 DOUBLE MAGNET() GENERATOR UNIT Wolfgang E. Sch, Longmeadow, and 'Charles Strniste, Agawam, Mass., assignors to American Bosch Corporation, Springneld, Mass., a corporation of New York Application May 2, 1942, Serial No. 441,422

4 Claims. (Cl. 171-209) This invention relates to double magneto generator units and more particularly to those of the geared intenupter type for high tension electrical ignition in multicylinder internal combustion engines.

One object of the invention is to provide a generator unit of this type in which both interrupter assemblies are arranged in an interrupter compartment located at the top of the magneto, whereby all parts of the assemblies are readily accessible from above for inspection, adjustment, repair and replacement, merely by removing the interrupter cap, and in which the electrical connectors connected to the high tension terminals of respective ignition coils of the generator are arranged in the generator compartment solely, whereby the low tension connections between the coils and the interrupter assemblies and the high tension connectors between the coils and vthe distributors in or for the generator unit are kept separate from each other and no high tension lconnector extends into or through the interrupter compartment.

Another object of the invention is to provide, if desired, a bearing plate and a supporting plate mounted in the frame of the magneto unit, or in the detachable upper housing section of the frame, to define within the frame a generator compartment below the bearing plate, a gearing compartment between the plates, and an interrupter compartment at the top of the unit just below a detachable interrupter cap. The advantages of these structural features are pointed out hereinafter.

Other improvements and advantages will be apparent from the following description of the preferred embodiment of the invention hereinbefore mentioned in which, as an example, the magneto generator unit is intended for association with an 18-cylinder 4stroke cycle .engine having two sparkplugs per cylinder and two 18- cylinder distributors therefor separately driven by the engine. In the accompanying drawings illustrating this embodiment,

Fig. 1 is a central vertical section, partly in elevation and partly broken away, of the magneto generator unit; Fig. 2 is acentral vertical sectionfpartly in elevation and partly broken away, of the generating section of the unit,

viewed at right angles to Fig. 1; Fig` 3 is a plan view of the interrupter assemblies in the interrupter compartment with the cap thereof removed; and Fig. 4 shows, on a reduced scale and somewhat diagrammatically, the magnetic circuit of the generator unit by which eight ignition impulses are generated per rotation of its magnetic rotor.

Referring to the drawings, the frame of the magneto generator unit comprises a generally elliptical-shaped shell I to which is fastened at the bottom by screws as 2 a flange 3 bolted in angularly adjusted positionto the frame 4 of the associated engine, and to which is fastened at the top by bolts 5 the housing 6 enclosing the interrupter and gearing compartments for the interrupter assemblies and their drive gearing. The two coil covers 1 and the interrupter cap 8, held in place by screws 9 and I0, respectively, complete the non-magnetic metallic enclosure of the interior parts of the generator unit. The bearing plate II for the lower ball bearing I2 for the generator rotor shaft I3 and the oil seal Il, are fastened by rivets as l5 to an upwardlyextending circular central portion I6 of the flange 3. The bearing plate I1 for the upper ball bearing I8 for the shaft I3 is held on a seat in the frame section I by the housing 6, and also supports the ball bearings I3 and 20 for the two vertical shafts 2I and 22 which have their rotational axes parallel to each other and to that of shaft I3. 'I'he supporting plate 23 supports the upper ball bearings 24 and 25 for the respective shafts 2I and 22 and is fastened on a seat in the housing 6 by screws 26. The plate I'I also separates the generating compartment 21 below it from the gear compartment 23 above it, and the plate 23 separates the latter from the interrupter compartment 23 above it and supports both interrupter assemblies except the cams as hereinafter noted.

Fast on the bottom end of the generator rotor shaft I3 is a pinion 30 adapted to be driven at a speed of rotation of that of the crank shaft of the associated engine. Fast on the upper end of the shaft I3, is a steel spur pinion 3l with helical teeth meshed with diametrically-opposite spur gears 32 and 33, also with helical teeth but each formed from a phenol or like material formed on a steel hub, as shown in Fig. 1, and requiring little or no outside lubrication. The pinion and gears lie in the same plane and thus form coplanar gearing, and the gear ratio is 8:18

between the generator rotor shaft I3 and each of the interrupter cam shafts 2|, 22, which terminate at their upper ends in the interrupter compartment, 29 and at their lower ends in the gearing compartment 28 or more specifically in the bearing plate I1. Thus the shafts 2l, 22 rotate at tig of the speed of shaft I3, and at half the speed of that of the engine crank shaft which is the same as that of the engine cam shaft.

As shown particularly in Fig. 4, the magnetic circuit of the generator, located in the generator compartment 21, includes a magnetic rotor 34 fast on the generator shaft I3 and composed o! steel laminations with four equally spaced radial poles 35. It also includes the stator comprising two permanent magnets 36 each clamped between laminated pole shoes 31 having upwardly and downwardly extending arms, across the pairs of which, as shown, are fastened lthe respective cores 33 and 39 of the high tension generating coils 40 and 4I composed of primary and secondary windings. These magnets, together with their pole shoes and arms, are cast-in the frame as disclosed in our copending application Serial No. 390,474, led April 26, 1941, and these coils with their cores are mechanically and electrically fastened to the arms as shown in- U. S. Patent 2,259,229. Each coil has a secondary or high tension metal terminal 42 or 43 which is contacted by the spring 44 of an electrical connector 45 for an outside shielded wire 46 (Fig. 1) which leads to the rotor of an 18-cylinder distributor (not shown) separately driven by the engine at the cam shaft speed of rotation thereof and which may be supercharged with compressed air. The nut 41 on the opposite side of the unit may be replaced by nipple connection to a pipe for supplying compressed air into the unit for supercharging it, or it may be interchanged with the connector 45 in case the wire 45 is to extend from the other side of the unit to eliminate mechanical interference with the devices of the power plant or to more suitably accommodate the wiring between the electrlcal devices associated with the engine. In either location of the connector, the bleed opening in the flange 3 at 65 (Fig. 2) provides for slow air leakage upon supplying compressed air for supercharging the unit. It will be observed that this magnetic circuit provides eight breaks per rotation of the magnetic rotor 34, or nine breaks per rotation of the engine crank shaft or eighteen breaks per rotation of the engine cam shaft. Also it will be observed that the air and surface leakage distances from the high tension terminals 42, 43, and from the electrical connectors 45, to the frame and other grounded parts are relatively great on account of their location within the generator compartment solely, and that this result is obtained without any increase therefor in the size, weight ar compactness of the generator unit, or in the accessibility of the generator parts when the coil covers 1, 8 are removed.

Located in the interrupter compartment 29 are two interrupter assemblies for the two coils 40 and 4I respectively, each assembly including an 1li-lobe cam 43 or 49 compensated for the best engine performance and fastened on its shaft 2| or 22. Above each cam and fast therewith is a timing collar 50, which is used in the well known way for indicating the time of opening of the interrupter contacts and for adjusting the edge distance of the generator. 'I'he cam lubrlcators I are generally of one of the manual types shown in Figs. lof the copending application of Frank S. Coe and Robert H. Gibson, Serial No. 430,172, iiled Feb. i0, 1942. Each interrupter assembly also includes an interrupter mounting plate 52 which is mounted on the supporting plate 23 and which is adjustable around its cooperative interrupter contacts in the well known way. The movable contact 53 is mounted A on the deilectable spring lever 54 and the its interrupter cam for concentric adjustment of 'l5 normally stationary contact 55 is carried by the bracket 56 adjustably mountedlon its plate 52 for adjusting the extent of opening of the cooperative contacts 53, 55. The spring-pressed hammer 51, which carries the cam follower 58 and is arranged to strike the lever 54 to separate the contacts upon actuation thereof by a cam lobe, is pivoted on the stud 59 carried by the plate 52. The live terminal post for the inter-- rupter assembly on the left in Fig. 3 is elecn tricaily connected by wire 5I to coil 40, and `the other live terminal post 62 is electrically connected by wire 53 to the other coil 4I. The upright condensers 54 are also mechanically and electrically fastened to respective plates 52 and are electrically connected to respective terminal posts 60 and 62.

Detachable connectors may be provided in the interrupter compartment 29 for making electrical connection between the respective terminal posts 60 and 52 and. starting vibrators and/or ground ing switches associated with the generator unit, and also automatic short circuiting devices for the respective interrupters may be provided as generally disclosed in our copending application Serial No. 415,542, filed October 18, 194.1.. These features are well known and are not shown herein.

It will be observed that, upon removing the interrupter cap 8, all parts oi both interrupter asn semblies and the associated devices therein and their electrical and mechanical connections, and more important the adjustments of the coopera tive interrupter contacts for the edge distance" of the magneto to best accord with the ma8- netic breaks of the rotor and stator poles of the magnetic structure of the generator as hereinbefore referred to, for the extent of their opening and for the setting thereof for synchronization of the simultaneous sparks of the unit lor the two sparkplugs in each of the engine cylinders, are readily accessible from above the unit for inspection and adjustment even while the generator unit is being driven by the engine to generate high tension ignition impulses in the cylinders thereof, and also for repair and replacement of the parts while the generator is at rest. It will also be observed that the bearing plate I1 and supporting plate 23 not only provide for carrying the bearings and for supporting the interrupter assemblies in part, as above noted, but also separate the interior of the frame into compartments in such wise as to make it easier to supercharge the generator compartment and to prevent the oil vapors in the gearing compartment from being deposited on the interrupter contacts 53, 55. Furthermore, the detachable housing 5 of the frame permits access to the gearing compartment without disturbing the gearing therein or the bearings in the bearing plate I1.

Although but one embodiment of the invention is herein disclosed, it will be obvious that many changes and modifications may be made Without departing from the spirit of the invention. For instance, the engine with which the magneto generator unit is associated may be of the 2-stroke cycle, for which the interrupter cam shafts will likewise have the speed of rotation of the cam shaft of the 4-stroke cycle engine hereinspecifically described. Also, the gearing, including the gear 30, through which the engine drives the magneto unit, may have any other desired ratio, it being understood, of course, that the ratio of the coplanar gearing 3|, 32, 33 will be changed accordingly to rotate th interrupter cams 48, 49 at the speed of rotation of the cam shaft of the engine. Also, the engine may have any other number of cylinders for which the associated magneto generator unit is adapted, and the two coils 4U, Il of the unit may be connected to interrupters arranged for sequential sparking at single sparkplugs in the engine cylinders, instead of simultaneous ignition as herein described at two sparkplugs in each engine cylinder. Also, the magneto generator unit may have any other suitable type of magnetic circuit, and the magnetic rotor may include the permanent magnets herein shown in the stator portion of the circuit. Also the distributors may be incorporated in any suitable way with the unit itself, instead of being separated therefrom and separately driven by the engine. Also the coplanar gearing herein disclosed may be replaced by any other suitable type of gearing providing the proper ratio between the vertical magnetic rotor and the vertical interrupter cam shafts. These and other modifications are intended to be included within the broad terms of the appended claims.

Having thus described the invention, what is claimed is:

l. In a double magneto generator unit of the geared interrupter type for high tension electrical ignition in a multicylinder internal combustion engine; a frame which provides within it a generator compartment, an interrupter compartment at its top, and a gearing compartment between the generator and interrupter compartments; a high tension generator which is arranged in the generator compartment and which includes a vertically arranged magnetic rotor adapted to be driven by the engine and also includes a stator structure with two high tension ignition coils and with magnetic members cooperative with the magnetic rotor; two interrupter cams shafts which extend vertically and which terminate at their bottom ends in the gearing compartment and at their top ends in the interrupter compartment; gearing which is arranged in the gearing compartment and which connects the magnetic rotor to the interrupter cam shafts with the gear ratio required to drive those shafts at the speed of rotation of the engine cam shaft; two interrupter assemblies arranged in the interrupter compartment and including multilobe cams fast on respective interrupter cam shafts and also including interrupter contacts which are mechanically cooperative with respective cams and which are electrically connected to the low tension terminals of respective coils; high tension connectors which are electrically connected to the high tension terminals of respective coils and which are arranged in the generator compartment solely; and an interrupter cap which is detachably fastened to the frame over the interrupter compartment and which is removable from the frame to expose the interrupter assemblies for inspection and ad- 'justment thereof while the generator unit is electrically operating to generate high tension ignition impulses in the cylinders of the engine.

2. In a double magneto generator unit of the geared interrupter type for high tension electrical ignition in a multicylinder internal combustion engine; a frame for housing the magneto unit; a bearing plate mounted in the frame and defining within the frame a generator compartment below the bearing plate; a supporting plate which is mounted in the frame and which defines a gearing compartment between the plates and also defines an interrupter compartment above the supporting plate; a generator which is arranged in the generator compartment and which includes a vertically arranged magnetic rotor Journaled in the bearing plate and adapted to be driven by the engine and also includes a stator structure with two high tension ignition coils and with magnetic members cooperative with the magnetic rotor; two interrupter cam shafts which are journaled in the bearing and supporting plates and which terminate at their bottom ends in the bearing plate and at their top ends in the interrupter compartment; gearing which is arranged in the gearing compartment and which connects the magnetic rotor to the interrupter cam shafts with the gear ratio required to drive those shafts at the speed of rotation of the engine cam shaft; two interrupter assemblies mounted in the interrupter compartment in part on the supporting plate and including multilobe cams fast on respective interrupter cam shafts and also including interrupter contacts which are mechanically cooperative with respective cams and which are` electrically connected to the low tension terminals of respective coils; high tension connectors which are electrically connected to the high tension terminals of the respective coils and which are arranged in the generator compartment solely; and an interrupter cap which is detachably fastened to the frame over the interrupter compartment and which is removable from the frame to expose the interrupter assemblies for inspection and adjustment thereof while the generator unit is electrically operating to generate high tension ignition impulses in the cylinders of the engine.

3. In a double magneto generator unit of the geared interrupter type for high tension electrical ignition in a multicylinder internal combustion engine; a frame which houses the magneto unit and which includes a detachable top housing member; a bearing plate mounted in the housing member and defining a generator compartment within the frame below it; a supporting plate which is mounted in the housing member and which defines within the housing member a gearing compartment between the plates and which also defines within the housing member an interrupter compartment above the gearing compartment; a high tension generator which is arranged in the generator compartment and which includes a vertically arranged magnetic rotor journaled in the bearing plate and adapted to be driven by the engine and also includes a stator structure with two high tension ignition coils and with magnetic members cooperative with the magnetic rotor; two interrupter cam shafts which are journaled in the bearing and supporting plates and which terminate at their bottom ends in the bearing plate and at their top ends in the interrupter compartment; gearing which is arranged in the gearing compartment and which connects the magnetic rotor to the interrupter cam shafts with the gear ratio required to drive those shafts at the speed of rotation of the engine cam shaft; two interrupter assemblies mounted in the interrupter compartment in part on the supporting plate and including multilobe cams fast on respective interrupter cam shafts and also including interrupter contacts which are mechanically cooperative with respective cams and which are electrically connected to the low tension terminals of respective coils; high tension connectors which are electrically connected to the high tension terminals of the respective coils and which are arranged in the generator compartment solely; and an interrupter cap which is detachably fastened to the housing member over the interrupter compartment and which is removable therefrom to expose the interrupter assemblies for inspection and adjustment thereof while the generator unit is electrically operating to generate high tension ignition impulses in the cylinders of the engine.

4. In a double magneto generator unit of the geared interrupter type for high tension electrical ignition in a multicylinder internal combustion engine; a frame which provides within it a generator compartment, an interrupter compartment at its top, and a gearing compartment between the generator and interrupter compartments; an interruptercap detachably fastened to the frame over the interrupter compartment; a high tension generator which is arranged in the generator compartment and which includes a vertically arranged magnetic rotor adapted to be driven by the engine and also includes a stator structure with two high tension ignition coils and with magnetic members cooperative with the magnetic rotor; two interrupter cam shafts which extend vertically and which terminate at their top ends in the interrupter compartment; gearing which is arranged in the gearing compartment and which connects the magnetic rotor to the interrupter cam shafts with the gear ratio required to drive those shaits at the speed oi rotation or the engine cam shaft; two interrupter assemblies arranged in the interrupter compartment and including multilobe cams fast on respective interrupter cam shafts and also including interrupter contacts which are mechanically cooperative with respective cams and which are electrically connected to the low tension terminals of respective coils; and high tension connectors which are electrically connected to the high tension terminals of respective coils and which extend through the side of that part oi the frame defining the generator compartment.

WOLFGANG E. SCHWARZMANN. CHARLES S'IRNIS'IE. 

